One of the chief features of superconducting wires is that they have extremely low (in the case of high-temperature superconductors) or zero (in the case of low temperature superconductors) resistance and hence dissipate little, if any, power. In many applications where they are used, it is necessary to monitor the current carried by the superconductor. The additional resistance and power dissipation associated with current-sensing systems, such as resistive current sensors, tends to defeat some of the advantage of using superconducting wire. Apparatus and techniques are needed to measure current in a conductor such as a superconducting wire in a straight forward manner without introducing additional resistance and power dissipation.